Christin A. Knowlton, MD, MA
Associate Professor of Therapeutic RadiologyCards
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Vice Chair for Accreditation, Therapeutic Radiology
Medical Director, Smilow Cancer Hospital Care Center-Hamden, Therapeutic Radiology
Chief, Breast Radiotherapy Program, Therapeutic Radiology
Contact Info
Therapeutic Radiology
PO Box 208040
New Haven, CT 06520-8040
United States
Are You a Patient?
View this doctor's clinical profile on the Yale Medicine website for information about the services we offer and making an appointment.
View Doctor ProfileAdditional Titles
Vice Chair for Accreditation, Therapeutic Radiology
Medical Director, Smilow Cancer Hospital Care Center-Hamden, Therapeutic Radiology
Chief, Breast Radiotherapy Program, Therapeutic Radiology
Contact Info
Therapeutic Radiology
PO Box 208040
New Haven, CT 06520-8040
United States
Are You a Patient?
View this doctor's clinical profile on the Yale Medicine website for information about the services we offer and making an appointment.
View Doctor ProfileAdditional Titles
Vice Chair for Accreditation, Therapeutic Radiology
Medical Director, Smilow Cancer Hospital Care Center-Hamden, Therapeutic Radiology
Chief, Breast Radiotherapy Program, Therapeutic Radiology
Contact Info
Therapeutic Radiology
PO Box 208040
New Haven, CT 06520-8040
United States
About
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Titles
Associate Professor of Therapeutic Radiology
Vice Chair for Accreditation, Therapeutic Radiology; Medical Director, Smilow Cancer Hospital Care Center-Hamden, Therapeutic Radiology; Chief, Breast Radiotherapy Program, Therapeutic Radiology
Biography
Dr. Christin Knowlton provides expertise in breast cancer radiation oncology and high-quality patient centered care in Hamden. She specializes in radiation therapy for breast cancer, lung cancer, bone metastases, and thymoma and says she was drawn to her field because it provides the opportunity to treat cancer often with tangible results. Dr. Knowlton says the best part of her job is meeting patients and answering questions about their disease process and treatment options. She received her medical degree from SUNY at Stonybrook. In 2019 she received the Smilow Luminary Award of Excellence in Patient Care.
Appointments
Therapeutic Radiology
Associate Professor on TermPrimary
Other Departments & Organizations
Education & Training
- Residency
- Hahnemann University Hospital/Drexel University College of Medicine (2011)
- MD
- SUNY at Stonybrook (2006)
- MA
- New York University, Education (1998)
- BA
- Oberlin College (1994)
Research
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Overview
Medical Research Interests
Research at a Glance
Yale Co-Authors
Publications Timeline
Research Interests
Nadine Housri, MD
Thomas Hayman, MD, PhD
Meena S. Moran, MD
Henry S. Park, MD, MPH
Lynn D. Wilson, MD, MPH, FASTRO
Suzanne B. Evans, MD, MPH, FASTRO
Breast Neoplasms
Publications
2025
P3.13.26 Sequencing of Stereotactic Body Radiation Therapy and Chemotherapy in Stage I Small Cell Lung Cancer: Practice Patterns and Outcomes
Ziaks T, Park H, Oh P, Hicks D, Knowlton C, Laird J, Hayman T. P3.13.26 Sequencing of Stereotactic Body Radiation Therapy and Chemotherapy in Stage I Small Cell Lung Cancer: Practice Patterns and Outcomes. Journal Of Thoracic Oncology 2025, 20: s516. DOI: 10.1016/j.jtho.2025.09.962.Peer-Reviewed Original ResearchCardiac Toxicity Following SBRT for Centrally Located Lung Tumors: Assessing the Impact of Radiation Dose Metrics
Shen J, Oh P, Hayman T, Knowlton C, Hicks D, Laird J, Park H. Cardiac Toxicity Following SBRT for Centrally Located Lung Tumors: Assessing the Impact of Radiation Dose Metrics. International Journal Of Radiation Oncology • Biology • Physics 2025, 123: e212. DOI: 10.1016/j.ijrobp.2025.06.3759.Peer-Reviewed Original ResearchConceptsStereotactic body radiotherapyCentrally located lung tumorsSingle-institution retrospective analysisNon-small cell lung cancerIncidence of cardiac eventsDose-volume histogramsOverall survivalCardiac eventsCoronary artery diseaseDose metricsHeart doseCardiac toxicityLung tumorsPatients treated with stereotactic body radiotherapySingle-institution retrospective analysis of patientsEarly-stage non-small cell lung cancerTreated with stereotactic body radiotherapyNew-onset atrial fibrillation/flutterRetrospective analysis of patientsDevelopment of cardiac eventsMaximum heart doseOligometastatic lung diseaseRadiation dose metricsSmall-volume dosesCentrally located tumorsRetrospective Study of the Efficacy and Safety of Lung Malignancy Radiation In-Field of Prior Ipsilateral Breast Radiation
Lawlor M, Park H, Knowlton C, Housri N, Hicks D, Laird J, Evans S, Hayman T. Retrospective Study of the Efficacy and Safety of Lung Malignancy Radiation In-Field of Prior Ipsilateral Breast Radiation. International Journal Of Radiation Oncology • Biology • Physics 2025, 123: e179-e180. DOI: 10.1016/j.ijrobp.2025.06.3687.Peer-Reviewed Original ResearchConceptsSafety of re-irradiationWhole breast radiationBreast radiationChest wall necrosisRe-IrradiationLocal recurrenceLung malignancyDose exposureRetrospective studyBreast radiation therapyWall necrosisCourse of radiationPrimary lung cancerCumulative dose exposureEffective local controlConcurrent palbociclibLung SBRTRadiation pneumonitisRefused surgeryRadiation therapyClinical toxicityFlap reconstructionPrimary endpointSecondary endpointsSurgical candidatesPercutaneous Cryoablation of Non-small Cell Lung Cancer in Patients with Recurrence After Stereotactic Body Radiation Therapy
Fish A, Park H, Knight E, Knowlton C, Madoff D. Percutaneous Cryoablation of Non-small Cell Lung Cancer in Patients with Recurrence After Stereotactic Body Radiation Therapy. CardioVascular And Interventional Radiology 2025, 48: 626-632. PMID: 40069339, DOI: 10.1007/s00270-025-04002-0.Peer-Reviewed Original ResearchCitationsAltmetricMeSH Keywords and ConceptsConceptsStereotactic body radiation therapyNon-small cell lung cancerCell lung cancerProgression-free survivalLung cancerPercutaneous cryoablationRadiation therapyOverall survivalTechnical successLocal controlNon-small cell lung cancer recurrenceHome oxygen requirementPost-procedure hospitalizationHistory of smokingWorsening pulmonary functionPost-procedural pneumothoraxEffective treatment alternativeConclusionPercutaneous cryoablationCryoablation protocolResults29 patientsTarget tumorsAdverse eventsCryoablationPulmonary functionLesion sizeModern-Day Hypofractionated Postmastectomy Radiation
Rybkin A, Bodofsky S, Knowlton C. Modern-Day Hypofractionated Postmastectomy Radiation. Current Breast Cancer Reports 2025, 17: 7. DOI: 10.1007/s12609-025-00570-9.Peer-Reviewed Original ResearchConceptsPostmastectomy radiationBreast cancerPost-mastectomy settingRegional nodal irradiationRadiobiological dataQuality of life metricsNodal irradiationBreast conservationEradicate tumorsComplication rateBrachial plexopathyPostmastectomy patientsToxicity profileHypofractionationFractionation schemaTherapeutic windowReviewThis reviewTissue effectsTrial dataBreastPostmastectomyStandard optionDisease controlPatientsCancer
2024
Complete vs. Incomplete Consolidative Radiotherapy in Patients with Extensive-Stage Small Cell Lung Cancer
Ninia J, Verma N, Laird J, Hayman T, Knowlton C, Peters G, Campbell A, Housri N, Feghali K, de Jong D, Park H. Complete vs. Incomplete Consolidative Radiotherapy in Patients with Extensive-Stage Small Cell Lung Cancer. International Journal Of Radiation Oncology • Biology • Physics 2024, 120: e51. DOI: 10.1016/j.ijrobp.2024.07.1890.Peer-Reviewed Original ResearchConceptsExtensive-stage small cell lung cancerProgression-free survivalSmall cell lung cancerOverall survivalCell lung cancerOligometastatic diseaseChemo-ImmunotherapyLung cancerSuperior progression-free survivalMedian follow-up timePatients treated with CCSites of disease involvementConsolidative thoracic radiotherapyAssociated with improved outcomesChemotherapy-based treatmentStratified Cox proportional hazard regressionsLog-rank testCox proportional hazards regressionDisease burdenTime of diagnosisKaplan-Meier estimatesProportional hazards regressionConsolidation radiotherapyPolymetastatic diseaseOligometastatic patientsRadioresistant Pulmonary Oligometastatic and Oligoprogressive Lesions From Nonlung Primaries: Impact of Histology and Dose-Fractionation on Local Control After Radiation Therapy
Verma N, Laird J, Moore N, Hayman T, Housri N, Peters G, Knowlton C, Jairam V, Campbell A, Park H. Radioresistant Pulmonary Oligometastatic and Oligoprogressive Lesions From Nonlung Primaries: Impact of Histology and Dose-Fractionation on Local Control After Radiation Therapy. Advances In Radiation Oncology 2024, 9: 101500. PMID: 38699671, PMCID: PMC11063223, DOI: 10.1016/j.adro.2024.101500.Peer-Reviewed Original ResearchCitationsAltmetricConceptsLocal recurrence-free survivalNon-lung primaryAssociated with higher local recurrence-free survivalProgression-free survivalBiologically Effective DoseLocal controlRadioresistant metastasesOverall survivalPulmonary metastasesPrimary cancerColorectal carcinomaAssociated with superior local controlMultivariate analysisPatients treated with radiotherapyRisk of local recurrenceMedian follow-up timeMultivariable Cox proportional hazards regressionInferior local controlMedian total doseSuperior local controlAssociated with decreased riskImpact of histologyMetastasis-free survivalRecurrence-free survivalLocal failureDose-volume Predictors of Radiation Pneumonitis Following Thoracic Hypofractionated Radiotherapy
Sasse A, Oh P, Saeed N, Yang D, Hayman T, Knowlton C, Peters G, Campbell A, Laird J, Housri N, Park H. Dose-volume Predictors of Radiation Pneumonitis Following Thoracic Hypofractionated Radiotherapy. International Journal Of Radiation Oncology • Biology • Physics 2024, 118: e5. DOI: 10.1016/j.ijrobp.2023.10.054.Peer-Reviewed Original ResearchCitationsConceptsHypofractionated radiation therapyRisk of gradeUltra-central tumoursRadiation pneumonitisLung V20Lung V5Central tumorsMultivariable logistic regression analysisSingle health care systemDose-volume predictorsDosimetric risk factorsGrade 5 toxicitySimilar local controlDose-fractionation regimensProbability of gradeProximal tracheobronchial treeLogistic regression analysisMATERIAL/METHODSHealth care systemPrimary endpointOverall survivalHypofractionated radiotherapyMultivariable analysisLung doseThoracic tumorsDosimetric Factors Associated with Esophagitis Following Hypofractionated Radiotherapy to the Thorax
Sasse, Oh P, Saeed N, Yang D, Peters G, Hayman T, Housri N, Laird J, Campbell A, Knowlton C, Park H. Dosimetric Factors Associated with Esophagitis Following Hypofractionated Radiotherapy to the Thorax. International Journal Of Radiation Oncology • Biology • Physics 2024, 118: e7-e8. DOI: 10.1016/j.ijrobp.2023.10.059.Peer-Reviewed Original ResearchConceptsHypofractionated radiation therapyTotal patientsOverall survivalLocal controlUltra-central lung tumorsMultivariable logistic regression analysisSignificant differencesComparable local controlGrade 3 esophagitisRisk of gradeCases of gradeProbability of gradeLogistic regression analysisMATERIAL/METHODSMean esophagus doseSingle healthcare systemEsophagus DmaxPrimary endpointHypofractionated radiotherapyDosimetric factorsMultivariable analysisEsophagus doseThoracic tumorsDosimetric variablesClinical trials
2023
Dose-Volume Predictors of Radiation Pneumonitis After Thoracic Hypofractionated Radiation Therapy
Sasse A, Oh P, Saeed N, Yang D, Hayman T, Knowlton C, Peters G, Campbell A, Laird J, Housri N, Park H. Dose-Volume Predictors of Radiation Pneumonitis After Thoracic Hypofractionated Radiation Therapy. Practical Radiation Oncology 2023, 14: e97-e104. PMID: 37984711, DOI: 10.1016/j.prro.2023.11.006.Peer-Reviewed Original ResearchCitationsAltmetricConceptsMean lung doseHypofractionated radiation therapyRisk of gradeRadiation pneumonitisLung V20Lung V5Dose-volume predictorsDosimetric risk factorsLogistic regression analysisGrade 5 casesSingle healthcare systemPrimary endpointDose regimensMultivariable analysisLung doseThoracic tumorsDosimetric variablesRisk factorsPneumonitisRadiation therapyCommon treatmentClinical practicePatientsSignificant associationPotential predictors
Clinical Trials
Current Trials
Phase IB/II Trial Of Dose-Deescalated 3-Fraction Stereotactic Body Radiotherapy For Centrally Located Lung Cancer
HIC ID2000025868RoleSub InvestigatorPrimary Completion Date01/31/2030Recruiting Participants
Academic Achievements & Community Involvement
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Honors
honor Smilow Luminary Award of Excellence: Patient Care
10/18/2019Other AwardSmilow Cancer HospitalDetailsUnited Stateshonor National Comprehensive Cancer Network (NCCN) Fellows Recognition Program
National AwardDetailsUnited States
Clinical Care
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Overview
Christin Knowlton, MD, is a therapeutic radiologist and is medical director of the Smilow Cancer Care Center in Hamden. Dr. Knowlton specializes in radiation therapy for breast cancer, lung cancer, bone metastases, and thymoma.
Dr. Knowlton says she was drawn to her field because it provides the opportunity to treat cancer “often with tangible results.”
“Radiation therapy is very successful at killing cancer cells and also helping with symptoms such as pain or bleeding from tumors,” she says. “In addition, some courses of radiation therapy span several days to weeks, which allows the physician the opportunity to really get to know the patients and their families.”
In fact, Dr. Knowlton says the best part of her job is meeting patients and answering questions about their disease process and treatment options.
“I also enjoy working closely with the members of the department of radiation oncology, including nursing, physics, dosimetry (treatment planning), and therapy to provide high-quality, patient-centered care,” she adds. “We work as a team to provide the best possible care for each patient.”
Clinical Specialties
Fact Sheets
Radiation Therapy
Learn More on Yale MedicineLung Cancer
Learn More on Yale MedicineBreast Cancer
Learn More on Yale MedicineLung Cancer in Nonsmokers
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Contacts
Therapeutic Radiology
PO Box 208040
New Haven, CT 06520-8040
United States
Administrative Support
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Patient Care Locations
Are You a Patient? View this doctor's clinical profile on the Yale Medicine website for information about the services we offer and making an appointment.